OPW M2010-EU, Installation Manual

Page: 140 / 149

Appendix H - 924B Probe Control Drawing
NOTES:
1. Entity Parameters:
(Vmax), Ui = 14.9V (Imax), Ii = 362mA
Ci = 0uf Li = 363uH
For Pi ≤ 1.3W -40°C ≤ Tamb ≤ 40°C
For Pi ≤ 1.2W -40°C ≤ Tamb ≤ 60°C
For Pi ≤ 1.0W -40°C ≤ Tamb ≤ 70°C
2. Associated Apparatus output current must be limited by a resistor such that the output voltage-current
plot is a straight line between open-circuit voltage and short-circuit current.
3. Selected Associated Apparatus must be third party listed as providing intrinsically safe circuits for the
application and have Voc or Vt not exceeding Vmax (or Uo not exceeding Ui), lsc or It not exceeding
Imax (or lo not exceeding Ii), and the Po of the associated apparatus must be less than or equal to the
Pmax or Pi of the intrinsically safe equipment as shown below.
4. Capacitance and inductance of the field wiring from the intrinsically safe equipment to the Associated
Apparatus shall be calculated and must be included in the system calculations as shown below. Cable
capacitance, Ccable, plus intrinsically safe equipment capacitance, Ci must be less than the marked
capacitance, Ca (or Co), shown on any associated apparatus used. The same applies for inductance
(Lcable, Li and La or Lo, respectively). Where the cable capacitance of inductance per foot are known,
the following values shall be used: Ccable = 60pF /ft., Lcable = 0.2uH/ft.
Use the following to determine the suitability of connections:
924B entity parameters Associated Apparatus
14.9V (Ui) ≥ Voc or Vt or Uo
362mA (Ii) ≥ Isc or It or Io
1.3W (Pi) ≥ Po
0uF (Ci)+Ccable ≤ Ca or Co
363uH (Li)+Lcable ≤ La or Lo
If Po of the associated apparatus is not known, it may be calculated using the following formula, Po=
(Uo*Io)/4
Example of a single 924B probe connected to a single position on the Associated Apparatus:
EXAMPLE:
Example Associated Apparatus 14.28V (Uo), 361mA (Io), 6.4uF (Co), 2,100uH (Lo)
Cable 1,000 feet, 60pF/ft, 0.2uH/ft = 0.060uF (60,000pf), 200uH
Doc. No.: M2010-EU Rev.: 13
Page 140 of 149