Load Factors - HP 3000 Series Handbook

For HP Internal Use Only
HP-18 Configuration Rules
Refer to Figure 4-6 for the following discussion.
Load Factors
Two load factors must be considered when calculating the cabling parameters of the HP-IB:
1. Internal Load Factor. The internal load factor of the Device adapter is seven loads.
2. External Load Factor. The external load factor of the peripherals is dependent upon the
individual peripherals and interconnect cables. (Refer to HP 3000 Computer Systems
Configuration Guide, P/N 5954-9354, Appendix 1 for peripheral load values.) A basic rule
for determining load values is you must have at least one electrical load for each meter of
HP-IB cable.
BACKPLANE
HP-IB PCA
DISK 2
F007
Figure 4-6. HP-18 Configuration Example
HP-IB Cable Length
The maximum total length of HP-IB cable that can be connected to a device adapter is 15
meters. When testing a configuration, use the following rules:
1. No more than eight HP-IB devices per HP-IB Device Adapter. It is recommended that no
more than six devices be connected.
2. Maximum of 15 device loads (internal
+
external).
3. Maximum HP-IB cable length must not exceed one meter per device load (maximum= 15
meters).
4. Daisy-chain (serial) cabling only
5. "Star" cabling not supported.
Configuration 4-11