CB Svendsen A/S
PT-Box Measurement of temperature via M-bus.
Product no. 95405600 (6 PT-500 inputs)
Introduction
The PT-box has 6 PT500 temperature sensor inputs
and one M-bus output. The PT-box enables
measurements of up to 6 temperatures via PT500
sensors. Measurements are digitized and
transferred to an M-bus master/logger for example
FA-40. As sensor elements, PT500 sensors can be
used from for example district heating meters. It is
possible to purchase aluminum blocks, which makes
it possible to convert round PT500 sensors to wire
clamp sensors (see thumbnail).
Function:
When the box via M-bus protocol is queried with an
M-bus command type “normalize”, the PT-box
performs immediate measurement of temperature
via the connected PT-500 sensor. The measuring
time for all 6 PT inputs are less than 1 second.
When the PT-box, after a “normalize” command,
gets prompted with an M-bus reading command, it
sends completely new measurements. The delay
depends on the M-bus master and it can be as little
as 1 second.
Measurement range and accuracy:
The measuring range is selected with jumper J3. Without jumper J3 the range is 0 to 120 degrees Celsius,
which are transferred scaled as degree Celsius with a typical accuracy of 0.2 degrees. Note without a
jumper on J3 the values which are measured below 0 gets sent as a value 0 and a measured value above
120 degrees, gets sent as a value 121.
With the jumper J3 the measuring range is -40 to +120 degrees Celsius, which are transferred scaled as
degree Kelvin with a typically accuracy of 0.4 degrees. Note with a jumper on J3 that a measured value
below 233.12K gets sent as a value 0 and a measured value above 393.15K gets sent as a value 394.
The accuracy applies PT-500 conversion i.e. exclusive measurement errors on the PT-500 sensor and
exclusive errors due to PT-500 cable.
Power supply:
The PT-box lives on M-voltage and uses 6 unit loads (total of 9mA)
Connection:
The M-bus is connected via 2 terminals and there are 2 further paralleled terminals for looping through the
M-bus. The PT-500 connections are of type 3-wire for cable resistance compensation. The cable type is
max. 0.75mm². PT-500 input no. 1 to 4 on the big horizontal terminal block. M-bus connections in and out
are on the left vertical terminal block and the PT-500 input no. 5 and 6 (if product number 95405600) is on
the right vertical terminal block.
Revision of 2015.08.02
Subject to change without notice!
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CB Svendsen A/S
Specifications:
New Software:
Firmware can be updated by service calls or by returning to service.
Standards/CE:
Safety:
Emission:
Immunity:
Temperature:
-20 to 45°C.
Relative humidity:
15 to 95% (none condensing)
Density:
IP44 (higher IP can be achieved by mounting a PG screw-joint)
Dimensions:
105*105*48 mm (W*H*D)
Remember: Clearance for cable entries.
Weight:
0, 2 kg
Revision of 2015.08.02
EN60950
EN50081-1 and -2
EN50082-1 and -2
Subject to change without notice!
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CB Svendsen A/S
Communication:
Interface:
Communication speed:
Communications frame:
Logical structure:
Selection of M-bus addresses:
Based on the M-bus standard DS/EN13757-1.
2400 bit/s (other speeds are not supported).
Standard M-bus (11 bits frame with start, stop, 8 data bit, even parity)
The 6 PT inputs on 2 logical M-bus units, each with its standard ”district
heating” meter M-bus telegram, whose addresses are selected via J2.
You can only choose between 2 sets of addresses and the choice can
only be via hardware – i.e. via J2:
Without jumper on J2:
PT-input T1, T2 and T3 will be added as TF, TR and TD from
logical unit on the primary address 201 and secondary address
90000201. PT-input T4, T5 and T6 will be added as TF, TR and
TD from logical unit on primary address 202 and secondary
address 90000202.
With jumper on J2:
PT-input T1, T2 and T3 will be added as TF, TR and TD from
logical unit on primary address 203 and secondary address
90000203. PT-input T4, T5 and T6 will be added as TF, TR and
TD from logical unit on primary address 204 and secondary
address 90000204.
Wild-card on primary addr.:
Logical unit on primary address 201 corresponds to wild-cart addressing
(FE), while logical unit on address 202/203/204 does not respond to
Wild-cart.
Wild-card on secondary addr.:
All logical unit supports Wild-cart search via secondary add.
Hint concerning FA-20/27/40/47: FA-20/27 uses Wild-cart and can only retrieve the logical address 201 i.e.
PT-input T1, T2 and T3 via FA-20 M-bus port M1 and/or M2. FA-40/47
can in mode B retrieve all 6 PT-inputs. The PT-box cannot be used via
Multi port on FA-20/27/40/47.
M-bus commands:
Init on wild-card primary address:
Init on primary address 201:
Init on primary address 202:
Init on primary address 203:
Init on primary address 204:
Deselect on primary add. 253:
1040FE3E16
1040C90916
1040CA0A16
1040CB0B16
1040CC0C16
1040FD3D16
Answer: E5
Answer: E5
Answer: E5
Answer: E5
Answer: E5
Answer: E5
Reading:
Wild-cart primary address:
105BFE5916
107BFE7916
105BC92416
107BC94416
105BCA2516
107BCA4516
105BCB2616
107BCB4616
105BCC2716
107BCC4716
105BFD5816
107BFD7816
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Answer: Readings
Primary address 201:
Primary address 202:
Primary address 203:
Primary address 204:
Primary address 253:
Selectivity secondary address:
When the logical unit is selected via secondary address, then it also
corresponds on primary address 253. If the logical unit hears another
device gets selected, then it deselects itself. Auto deselecting occurs
after 60 seconds.
Revision of 2015.08.02
Subject to change without notice!
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CB Svendsen A/S
Selectivity command:
680B0B68 53FD52 xxxxxxxx FFFFFFFF <CHECKSUM> 16
(xxxxxxxx = secondary address LSB first).
680B0B68 53FD5201020090FFFFFFFF 31 16
Answer: E5
680B0B68 53FD5202020090FFFFFFFF 32 16
Answer: E5
680B0B68 53FD5203020090FFFFFFFF 33 16
Answer: E5
680B0B68 53FD5204020090FFFFFFFF 34 16
Answer: E5
Other M-bus commandos:
Ignored.
Standard M-bus Readings from the PT-Box (identical for -6 and -4 variants):
Name:
Start byte
L-Field
L-Field
Start byte
C Field
A Field
CI Field
Secondary address
Manufactory code
SW version
Medium
Access no.
Status
Length:
1
1
1
1
1
1
1
4
2
1
1
1
1
Value:
68h
34h
34h
68h
08 h
Ex. C9 h
72 h
Ex. 01.02.00.90
53.0C h
01 h
04 h
-- h
-- h
Signature
2
0000 h
Description:
Standard M-bus start byte
Length of response [58-6=52dec = 34h]
Length of response (Copy)
Standard M-bus start byte
M-bus response with measurement data
Primary address: 201..204dec = C9..CCh
12 byte header + variable format data
8 BCD [90000201..90000204]
0C53h = CBS short for CB Svendsen
Firmware version nr.
District heating meter
Binary counter for M-bus access [00..FF]
Bit 2 = Power failure (Unstable power)
Bit 3 = Permanent failure (FRAM etc.)
Bit 4 = Transient failure (watch-dog etc.)
Encryption: Not supported
1
0A h
BCD 4 digits
1
2
5A h
xx.xx h
TF in 0,1 degree resolution. J3)
2 byte 4 digits BCD (LSB first)
1
1
2
0A h
5E h
xx.xx h
BCD 4 digits
TR in 0.1 degree resolution. J3)
2 byte 4 digits BCD (LSB first)
1
1
2
0A h
62 h
xx.xx h
BCD 4 digits
TD in 0,1 degree resolution. J3)
2 byte 4 digits BCD (LSB first)
1
24
1
0F h
Xx h
Manufacture defined data
For development use/ debug in the field
Check Sum (As defined in M-bus)
1
16 h
Stop byte (As defined in M-bus)
T1 or T4:
DIF
VIF
Value
T2 or T5:
DIF
VIF
Value
T3 or T6:
DIF
VIF
Value
User define:
DIF
Reserve
Check Sum
Stop byte
Red fields: Dynamic fields (Black fields are static).
J3):
Jumper on J3: It is only the numeric value that is changed by addition of +273.15 complete
with rounding – not VIF
Revision of 2015.08.02
Subject to change without notice!
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