model 2704 controller installation and operation handbook - Soliton

2704 Controller Safety and EMC Information
B.3.
INSTALLATION SAFETY REQUIREMENTS
B.3.1. Safety Symbols
Various symbols are used on the instrument, they have the following meaning:
!
Caution, (refer to the
accompanying documents)
Functional earth
(ground) terminal
The functional earth connection is not required for safety purposes but to ground RFI filters.
B.3.2. Personnel
Installation must only be carried out by qualified personnel.
B.3.3. Enclosure of live parts
To prevent hands or metal tools touching parts that may be electrically live, the controller
must be installed in an enclosure.
B.3.4. Isolation
The fixed digital I/O and analogue input are not isolated. The PV Input and all plug in
modules are fully isolated. This is shown in Figure B-1.
The Analogue Input is a self biased differential input suitable for either grounded or floating
transducers of low output impedance generating signal in the range of +/-10V or +/-20mA
(with a burden resistor of 100 Ohms across + and - terminals).
This input is neither isolated from the instrument ground (which can be earthed via fixed I/O
ports) nor isolated from the instrument earth terminal, therefore, under no circumstances
should mains potentials be applied to any of its inputs.
In order for the Input to operate safely the common voltage at the inputs measured with
respect to instrument ground should not exceed +/-120Vdc or ac rms
. For actively enhanced
common mode rejection (i.e. operation within the spec.) this voltage should be limited to +/-
40Vdc.
Floating transducers will automatically be biased to +2.5V with respect to instrument ground
upon connection.
Note: All the other I/Os are fully isolated from the instrument ground and each
other.
Engineering Handbook. Part No HA026502 Issue 2.0 Apr-00 B-3