Servomex 1100A Instruction Manual page 46

Cable requirements are:-
1. Seven twisted pairs with an overall shield or screen with drain wire. In electrically noisy
installations it may be necessary to shield each individual pair.
For analysers without pressure compensation, five twisted pairs only are used.
2. The recommended conductor size is 16/0.2mm (20 AWG), but others are acceptable
provided the cross-sectional area of the conductor is within the range 0.5 to 1.5mm (20
to 16 AWG) and the loop resistance does not exceed 10 ohms.
Note: The loop resistance of 100m of 16/0.2mm (20 AWG)
3. The maximum length of the cable is 100m (330ft).
4. If pressure compensation is fitted this cable should not exceed 30m (100ft) otherwise
performance will be degraded.
2.8.1.1 UK Certification Requirements - Hazardous Area Use
This cable should comply with BS 5308 (Instrumentation Cables). The cable must meet the
requirements for a type 'A' or 'B' cable as defined in BS 5501, Part 9, 1982 (EN 50039), clause
5.3 and be correctly installed.
Capacitance and inductance or inductance to resistance (L/R) ratio must not exceed the following
values:
For H /O mixtures:
2 2
Gas group
IIC
IIB
IIA
See certification details in Suplementary manual 01100 008A for conditions of use, in particular
Certificate Ex 84394/2 (10 February 1988).
2.8.1.2 CENELEC Certification Requirements
The cable must meet the requirements for a type 'A' or 'B' cable as defined in EN 50 039, clause
5.3 and be correctly installed.
2.22
cable is approximately 8 ohms.
Capacitance
: F
0.02
0.06
0.16
Inductance or L/R ratio
mH
0.82
2.46
6.56
: H/ohm
15.6
46.8
124.0