Because of the high peak power consumption (when turning on or during printing) and possibility to overload the UPS, it is not recommended to connect laser printers to the UPS output. However when there is a need to protect laser printer, it should be True-On-line UPS with big power redundancy (couple kVA).
The power of all loads that are to be protected has to be added together. Power in VA of each device can be found on a nameplate; if the power is not given we can calculate it by multiplying voltage by current. If power is given in watts [W], then we multiply this by 1.4 (typically for computer-type loads), to get the power in VA. It is recommended that the power of UPS was bigger by at least 20% of the total power of all loads.
From 2015, COMEX is responsible for design of new devices, solutions production in cooperation with partners from the Far East and sales operations of COVER brand.
Using UPS with software ensures full computer system protection. In case of the power outage software will inform the user about it by displaying a message on the screen. If outage lasts longer software will automatically, without any user action, shutdown the system – this is basic and most important aim of using software in UPS system. System is also shut down when batteries are almost empty. After mains come back, UPS automatically switches on and turns on computer. So it is clear that software in UPS ensures safe and maintenance-free work of whole computer system.
It depends on the type of the communication port of the UPS. If the interface is Dry Contacts type („dumb mode”) then UPS status is signaled through the simulation of short circuit of pins. Usually no voltage is most often alarm or low battery level, it is also possible to turn off UPS. If there is RS232 interface (“smart mode”), communication between UPS and computer is carried out through asynchronous two-way serial communication. Then it is possible to see in real-time input voltage, voltage on batteries or load; by software user can control operation of the UPS and for example turn on battery test.
SNMP adapter (SNMP – Simple Network Management Protocol) allows for remote control of UPS work through computer network. By using NMS (Network Management System) software, or special, dedicated software, user can control all UPSes equipped with SNMP adapter in the network from one station. Additionally one UPS compatible with SNMP (that is equipped with SNMP adapter) that is connected to multiple computers can be monitored through software on couple of serves and in case of power outage all servers will be automatically shut down.
In the popular equipment group standard lifespan of the batteries declared by the manufacturer is from 3 to 5 years (assuming exploitation in proper conditions). The biggest impact on the battery lifespan has got environment temperature during operation. If it is higher than 20°C it will reduce the expected lifespan. Optimal operation temperature for batteries is 15°C - 20°C. Charging/discharging cycle also has got significant impact on the lifespan of batteries. In the popular equipment number of full dischargings is estimated at 180-200, that is why full dischargings should be avoided during UPS operation in battery mode.
It is not recommended to connect Surge protector power strips (i.e. ACAR type) to the UPS output, because UPS has got this functionality already built-in. In case we are using off-line or line-interactive type of UPS, inductivity in the strip filter can disrupt UPS operation. However strips can be connected before the UPS.
Unconditionally yes – this is required because of the safety issues. If we do not ground UPS, the computer system that is protected will not be grounded either. It can create danger for the user and equipment connected to the computer.
In general every case has to be looked into individually. It all depends on the requirements and priorities. From purely economic perspective it is easier and cheaper to equip every work station with small off-line or line-interactive UPS. However it has to be taken into consideration that maintenance of that kind of system is quite complex. On the other hand installation of one central big power UPS requires separate, dedicated electrical network. But it significantly simplifies operation and maintenance of the system. Additionally the voltage that powers the loads will always be of the highest quality and in case of the overload UPS will work in bypass mode and power the loads from the mains.