Rfi Immunity - Cardinal 225 Installation And Technical Manual

SITE PREPARATION REQUIREMENTS, CONT.

RFI Immunity

The operation of sensitive electronic equipment can be adversely affected by RF (Radio
Frequency) radio transmissions. Digital weight indicators are one such type of equipment.
Radio transmissions come from things like hand-held radio transmitters and cell phones. One
symptom of RFI (Radio Frequency Interference) in a digital weight indicator is weight indication
instability during a radio transmission.
Cardinal digital weight indicators are designed with special grounding and RFI shielding to
achieve a high degree of immunity to common RFI. To maximize the digital weight indicator's
immunity to radio transmissions, follow these guidelines:
1. ALWAYS use shielded cable for all I/O (Input/Output) connections to the digital weight
indicator.
2. NEVER operate any radio transmitter within 2 meters (~6ft.) of the weight indicator.
3. NEVER connect un-terminated serial, digital, or analog I/O cables to the internal printed
circuit boards of the digital weight indicator.
4. KEEP the intended external I/O device connected to I/O cables entering the digital
weight indicator.
5. ALWAYS connect the shield of the shielded cable to the indicator back panel gland
connector or other closest ground terminal inside the indicator.
6. ALWAYS connect the shield of the shielded I/O cable at the indicator end only. Leave
the shield unconnected at the I/O device.
6 8200-M698-O1 Rev B  225 Installation and Technical