Gill Instruments Ltd
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MetPak/MetPak RG and MetPak Pro Base Stations
Page | 21
Issue 1
Doc. No. 1723-PS-0023
October 2018
4.3.1 Communication and Power Cable type
Wire type:
24 AWG
Wire size:
7x32 AWG.
Cable outer diameter:
6- 8mm (to match the connector gland).
For RS422/485 operation the cable should have twisted pairs with drain wire, screened with
aluminised tape, with an overall PVC sheath. Typical wire size 7/0.2mm (24 AWG).
The following table shows an example manufacturers’ reference; other manufacturers’ equivalents
can be used.
Recommended Belden cable types
4.3.2 Cable Length
The maximum cable length is dependent on the chosen communication method.
The following table shows the maximum cable lengths for the supported communication protocols
at the given baud rates, using the recommended cable. If any problems of data corruption etc. are
experienced, then a slower baud rate should be used. Alternatively, a higher specification cable
can be tried.
Suggested maximum cable lengths for supported communication networks
Communication format
Baud rate
Max. cable length
RS232
19200
6.5M
RS422/485
19200
1000M
SDI-12
1200
90M
0-5v Analogue Input
Not Applicable
Refer to user Analogue Sensor data sheet
4-20mA Analogue Input
Not Applicable
Refer to user Analogue Sensor data sheet
Digital Switch Input
Not Applicable
Switch contact and cable resistance to be less
than 1k ohm
PRT Input
Not Applicable
Refer to user PRT data sheet
Application
No. of Pairs
24 AWG Belden Ref.
SDI-12
2
9729
Digital RS232 or RS485
3
9503
Digital RS422
4
9504
Multiple External Sensors
6
9506
